NAME
mincore - determine whether pages are resident in memory SYNOPSIS
#include
#include
int mincore(void *addr, sizet length, unsigned char *vec); Feature Test Macro Requirements for glibc (see featuretestmacros(7)): mincore(): BSDSOURCE || SVIDSOURCE DESCRIPTION mincore() returns a vector that indicates whether pages of the calling process's virtual memory are resident in core (RAM), and so will not cause a disk access (page fault) if referenced. The kernel returns residency information about the pages starting at the address addr, and continuing for length bytes. The addr argument must be a multiple of the system page size. The length argument need not be a multiple of the page size, but since res‐ idency information is returned for whole pages, length is effectively rounded up to the next multiple of the page size. One may obtain the page size (PAGESIZE) using sysconf(SCPAGESIZE). The vec argument must point to an array containing at least (length+PAGESIZE-1) / PAGESIZE bytes. On return, the least signifi‐ cant bit of each byte will be set if the corresponding page is cur‐ rently resident in memory, and be clear otherwise. (The settings of the other bits in each byte are undefined; these bits are reserved for possible later use.) Of course the information returned in vec is only a snapshot: pages that are not locked in memory can come and go at any moment, and the contents of vec may already be stale by the time this call returns. RETURN VALUE
On success, mincore() returns zero. On error, -1 is returned, and errno is set appropriately. ERRORS EAGAIN kernel is temporarily out of resources. EFAULT vec points to an invalid address. EINVAL addr is not a multiple of the page size.
ENOMEM length is greater than (TASKSIZE - addr). (This could occur if a negative value is specified for length, since that value will be interpreted as a large unsigned integer.) In Linux 2.6.11 and earlier, the error EINVAL was returned for this condition. ENOMEM addr to addr + length contained unmapped memory. VERSIONS Available since Linux 2.3.99pre1 and glibc 2.2. CONFORMING TO
mincore() is not specified in POSIX.1-2001, and it is not available on all UNIX implementations. BUGS Before kernel 2.6.21, mincore() did not return correct information for MAPPRIVATE mappings, or for nonlinear mappings (established using remapfilepages(2)). SEE ALSO mlock(2), mmap(2) COLOPHON
This page is part of release 3.53 of the Linux man-pages project. A description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
Linux 2008-04-22 MINCORE(2)